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EASC 102 Physical Geography
SFU
87
Geology
Undergraduate 1
01/09/2013

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Cards

Term
What is a rock?
Definition
A rock is an aggregate of ONE OR MORE minerals.
Term
What are some examples of rocks composed of more than one mineral?
Definition
ex. feldspar, quartz, mica
Term
What are some examples of rocks composed of only one mineral?
Definition
ex. limestone, marble (both made of calcite)
Term
What is the definition of mineral?
Definition
A mineral is naturally occurring, inorganic, solid, and has a definite or very narrow range of chemical composition. Atoms must be arrange in a repeating pattern.
Term
What are the mineral properties and why are they useful?
Definition
The mineral properties are cleavage, hardness, lustre, crystal form, reaction to HCL, and streak. Colour is not a property because it tends to vary. Properties are used to identify minerals.
Term
What is the definition of cleavage?
Definition
minerals break along planar surfaces (smooth). this is due to an alignment of bonds within minerals -> surfaces of weakness.
Term
What is the definition of a fracture?
Definition
minerals do NOT break along planar surfaces, instead there are random jagged bits (irregular). or it breaks along smooth, curved surfaces -> conchoidal fractures.
Term
Can a mineral break with both cleavage and fractures?
Definition
yes. in some directions there can be cleavage, in some there could be fractures.
Term
What is the definition of hardness?
Definition
the ease with which a metal can be scratched
Term
What is Mohs Hardness Scale?
Definition
a scale of 10 minerals that have a varying range of hardness.
Term
List the hardness scale from 1 to 10.
(hint: Tall Girls Can Force Apart Oreos Quicker Than Clumsy Dudes)
Definition
talc
gypsum
calcite
fluorite
apatite (also your teeth)
orthoclase (feldspars)
quartz
diamond
Term
Where on the hardness scale is your fingernail?
Definition
2.5
Term
Where on the hardness scale is a copper penny?
Definition
3.5
Term
Where on the hardness scale is a wire nail?
Definition
4.5
Term
Where on the hardness scale is a streak plate?
Definition
6.5
Term
Where on the hardness scale is a glass plate?
Definition
5.5
Term
What is the definition of lustre?
Definition
how a mineral reflects light, either metallic or nonmetallic reflection of light.
Term
What can be said about metallic lustre?
Definition
a metallic colour also means a metallic reflection (silver, gold, bronze)
Term
What can be said about nonmetallic lustre?
Definition
nonmetallic is light or dark coloured, shiny or dull, but not metallic.
Term
What defines submetallic?
Definition
it breaks in sheets, is dark in colour (like a nonmetallic) but shines like a metal.
Term
What defines crystal form?
Definition
the shape a mineral will grow ONLY if the mineral grows into unrestricted, open space. most of the time they interlock with other minerals.
Term
How can you tell apart a crystal or a cleavage fragment?
Definition
broken minerals (NOT CRYSTALS) show geometric shapes because they have cleavages. look to see if there are any fractures on the surface, if they are not the same as the mineral's fractures it is a crystal probably.
internal weaknesses
Term
What is the definition of 'reaction to HCl'?
Definition
some minerals will react with dilute HCl.
Term
What is the definition of a streak test?
Definition
the colour of the powdered form of the mineral in question. the powder is often a different colour than the mineral in solid form.
ex: hematite is silver, streak is red
Term
Why is colour not a useful way to identify a mineral?
Definition
it is typically variable for most minerals
Term
What are some other properties that can be used to identify a mineral?
Definition
magnetism, optical properties
Term
What are the 7 major mineral classes?
Definition
silicates, native elements, oxides, sulfides, halides, carbonates.
Term
What are silicates?
Definition
must contain Si and O in some combination.
Term
How common are silicates and why?
Definition
95% of minerals in earth's crust are silicates. The earth's crust is made primarily of silicon and oxygen -> silicates.
Term
What basic shape are silicates made of?
Definition
The silica tetrahedron.
Term
What are some characteristics of silica tetrahedra?
Definition
has an overall charge of -4 -> can't exist on its own, must bond with cations to balance the charge, or bond to oxygen to share electrons.
Term
What are the two classes of silicates?
Definition
nonferromagnesian and ferromagnesian silicates. (ferromagnesian silicates contain Fe and sometimes Mg)
Term
What are native elements?
Definition
minerals containing only a single element, like copper, gold, silver etc.
Term
What are oxides?
Definition
they contain oxygen, ie. ice, hematite, corundum.
Term
What are sulphides?
Definition
they contain sulphur, ie. pyrite, galena, etc.
Term
What are halides?
Definition
contain either chlorine, fluorine, bromine or iodine. (the halides)
ie. fluorite, halite etc.
Term
What are carbonates?
Definition
contain CO3, ie. calcite, malachite.
Term
What are mineral groups?
Definition
minerals that are similar CHEMICALLY and have the same crystalline structure are in the same group. they also have the same cleavage (based on atomic structure)
example: the feldspar group. all feldspars contain Si3O8, and each variety of feldspar contains varying amounts of other elements.
Term
Give an example of a mineral group divided into species.
Definition
ex. feldspar species - potassium (k-spar), plagiocase (plag)
Term
What are the 7 common rock-forming mineral groups?
Definition
olivine, pyroxene, amphibole, micah, feldspar, quartz, and calcite
Term
Is the olivine group ferromagnesian or nonferromagnesian?
Definition
ferromagnesian silicates
Term
What characterizes the olivine group?
Definition
they are commonly found as small grains within rocks
under the microscope, they are translucent green and have conchoidal fractures (looks like glass)
Term
Is the pyroxene group ferromagnesian or nonferromagnesian?
Definition
ferromagnesian silicates
Term
What characterizes the pyroxene group? what variety will we see in lab?
Definition
grains tend to be black or dark green, not translucent.
broken grains have 2 cleavages at 90 degrees

we'll be seeing AUGITE (the most common)
Term
Is the amphibole group ferromagnesian or nonferromagnesian?
Definition
ferromagnesian silicates
Term
What characterizes the amphibole group? what variety will we see in lab?
Definition
black and dark green
broken grains have 2 cleavages NOT at 90 degrees (56/124)

we'll be seeing HORNBLENDE
Term
Is the micah group ferromagnesian or nonferromagnesian?
Definition
both!
Term
What is the ferromagnesian type of micah?
Definition
biotite - it is blackish coloured.
Term
What is the nonferromagnesian type of micah?
Definition
muscovite - it is clearish coloured.
Term
How does micah break?
Definition
into sheets - 1 cleavage
Term
Is the feldspar group ferromagnesian or nonferromagnesian?
Definition
nonferromagnesian silicates!
Term
What are the 2 species of feldspar?
Definition
potassium feldspars and plagioclase feldspars
Term
What are the characteristics of feldspars?
Definition
colours vary way too much
break at 2 cleavages, 90 degrees
Term
Is the quartz group ferromagnesian or nonferromagnesian?
Definition
nonferromagnesian silicate!
Term
What are some characteristics of quartz?
Definition
second most abundant in earth's crust
VERY HARD (7 on scale)
breaks with conchoidal fractures
colours are highly variable
Term
Is the calcite group ferromagnesian or nonferromagnesian?
Definition
NEITHER!!!!! it is carbonate!!!!!
Term
What are some characteristics of calcite?
Definition
precipitated calcite forms sedimentary rock limestone
it has 3 cleavages not 90 degrees (rhombic shape)
reacts to dilute HCl
Term
Who developed the continental drift hypothesis and when?
Definition
alfred wegener , 1915
Term
What does the continental drift hypothesis state?
Definition
about 200 million years ago, all continents were massed together as pangaea. since that time continents have drifted to their current locations
Term
What was Wegener's evidence for continental drift?
Definition
fit of the continents, matching up mountain ranges, fossils, glacial deposits, paleoclimate belts
Term
Why was the theory rejected by the scientific community?
Definition
Wegener had no answer to WHY the continents were moving.
Term
Who developed the tectonic plate theory?
Definition
many researchers over several years
Term
What really started the tectonic plate theory?
Definition
They had to map the seafloor during WWII, so they could hide submarines. since they mapped it they ended up having a way to look at the plates.
Term
What did Harry Hess do and then discover?
Definition
mapped portions of the seafloor and found massive ridges instead of flat
Term
What did Hess do in 1962?
Definition
proposes that MORs he mapped were locations where new ocean crust was being formed and old oceanic crust sunk back into earth at deep ocean trenches.
Term
What else did Hess propose about plate tectonic theory?
Definition
the mechanism for movement is mantle convection, where squishy hot rock rises and moves along surface, cools down, falls and then heats up again
Term
What did Matthews and Vine do in 1963?
Definition
presented paleomagnetic data from seafloor as evidence of spreading.
Term
What causes the earth's magnetic field?
Definition
as lava cools below 768 degrees, iron aligns itself with the existing polarity, and then the magma protrudes from the MORs and locks into direction of magnetic field
Term
How does earth generate magnetism?
Definition
liquid iron in outercore spins as earth does, generating magnetism.
Term
What causes weakening and reversal in the magnetic field?
Definition
there are big storms in the outer core that mess up the rotation, spinning can change directions.
Term
How did Matthews and Vine get the data for their explanation of the magnetism of the earth?
Definition
they dragged a magnetometer along the ocean floor and recorded the paleomagnetism locked in the crust.
Term
How is the data from the magnetometer read?
Definition
positive anomalies indicate the same polarity as present.
negative anomalies indicate the opposite polarity as present.
Term
What else does the data from the magnetometer prove?
Definition
Since magnetic anomalies occur in stripes going out of the MORs, we can conclude that spreading occurs there
Term
When was the last flip in the magnetic field?
Definition
more than 50 000 years ago
Term
What does the magnetic field do?
Definition
protects us from solar flares etc
Term
What did Tuzo Wilson discover in 1963?
Definition
hot spots
Term
How did Tuzo Wilson discover the hot spots?
Definition
he explained the presence of active volcanism far away from plate margins, because of deep mantle hotspots that the area travels over. magma flows up and produces a chain of volcanoes that increase in age away from the active hotspot.
Term
Does a hotspot move?
Definition
nope! the plate moves and makes new islands.
Term
What did Tuzo Wilson predict in 1965?
Definition
the presence of transform faults connecting offset segments of MORs
Term
Why do transform faults exist?
Definition
because spreading around a sphere means you can't subduct it all at the same rate, the MOR cannot connect in one big line.
Term
How were transform faults confirmed?
Definition
Vine and Matthews used paleomagnetic data off the west coast of North America.
Term
What happens at mid ocean ridges?
Definition
Diverging (new materials)
Term
What happens at deep ocean trenches?
Definition
Converging (old materials recycled)
Term
How else do we know that new material is near the MORs?
Definition
Deep sea drilling to remove rock from the floor.
Term
Where are sediments thinnest on the ocean floor?
Definition
thinnest near the ridge crest, thickest further away.
Term
How do we measure the distance of spreading and in what units?
Definition
Satellites; cm/year (very slow)
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